In competitive races I agree, but there are odd cases where voting uninformedly might be better than not voting, though you can always leave particular parts of the ballot blank. If your vote doesn't actually sway the race, then in effect you're only voting for your demographic to be taken more seriously in the next election's "likely voter" screen that pollsters use, which is probably in your interests to do (this is one reason the elderly get disproportionate weight in politics, because they vote at high rates).